UM....

WHO IS THIS?!

So he's related to Natsu and Zeref...

HOW?

If he's their brother, then he couldn't have lived with Natsu and Zeref. Maybe he was sent away at a very young age and the boys don't remember? Or maybe they weren't even born yet?

It could be their dad. He could have lived, and judging by the picture, he looks older then Natsu and Zeref.

THEN AGAIN, he would needed to have either lived for 400 years or travelled 400 years in the future.

I think (this will be confusing) that Natsu's father's BROTHER is that Dragneel's descendant. It would make sense, if Dad Dragneel had a brother, he couldn't have died in the fire, and the family name could be carried on if they take the Dragneel name.

Although that would make sense, I'm sure Hiro has something elaborate up his sleeve for the new Dragneel...